A known electronic device mounting board includes an inorganic substrate and a frame having an opening. The inorganic substrate and the frame are typically joined with a bond. A known electronic package includes such an electronic device mounting board, on which an electronic device is mounted and having a lid covering the upper surface of the frame to close the opening (refer to Japanese Unexamined Patent Application Publication No. 5-326772).
Recent electronic devices with more sophisticated functions tend to generate more heat during operation. With the technique described in Unexamined Patent Application Publication No. 5-326772, heat generated from an electronic device is mostly transferred to an inorganic substrate. The heat transferred to the inorganic substrate may be further transferred to the frame through the bond. The heat transferred to the frame can change the temperature of the conductors inside and outside the frame, and change the resistance of the conductors.